GENERAL PROPERTIES OF PROTOZOA & HELMINTS

1. GENERAL PROPERTIES OF PROTOZOA & HELMINTS Doç.Dr.Hrisi BAHAR

2. GENERAL PROPERTIES OF PROTOZOONS Doç.Dr.Hrisi Bahar

3. General Characteristics ●Unicellular animal with full functions ●Distribute widely: water,soil, etc. ●Total species 65,000 • Free-living: majority • Parasitic: about 10,000

4. General Characteristics ●Size 2 - 100 micrometers ● Parasitic protozoa are most facultative anaerobes; ●Mostly heterotrophic,chemoorganotrophs ●Nutrients assimilated via phagocytosis, pinocytosis, diffusion ●Digestion may be bothextracellular and intracellular.

5. Medical Protozoa ●Pathogenic protozoa ●Opportunistic parasite • Not normally pathogens • Become pathogenic due to impairment of host resistance • Clinical importance of the AIDS epidemic

6. Basic Structures ●Plasma membrane ● Cytoplasm • Ectoplasm: locomotion , ingestion, etc • Endoplasm: metabolism ● Nuclear • Vesicular form or compact form ● Locomotive organelle • Pseudopodium, flagellum, cilia

7. Protozoon

8. Mode of Reproduction ●Asexual reproduction • Binary fission: results in 2 daughter cells • Schizogony: multiple fission, results in multiple cells ●Sexual reproduction • Conjugation: exchange of nuclear materials of 2 cells • Gametogony : sexually differentiated cells unit  zygote

9. Life Cycle Patterns ●One stage form • Trophozoite ( =vegetatif form.Take food, be mobile, multiply) ●Two-stage form • Trophozoite & cyst (not mobile, with cyst wall. cyst=protective form) ●Two-host form • Mammals – mammals • Mammals - insect vectors

10. Site of infections ●Gastrointestinal system (E.histolytica,B.coli,G.intestinalis,D.fragilis, Cryptosporidium,Isospora,Blastocystis,Sarcocystis, Microsporidia) ●Urogenital system(T.vaginalis) ●Blood(Plasmodium,babesia) ●Tissue(T.gondii,Leishmania sp,E.histolytica, Naegleria sp,Acanthamoeba sp)

11. A-The Sarcomastigophora (Amoeboflagellates) • 1-Sub phylum Sarcodina (The amoebas) • Motility via Pseudopoda • Extensions of the cell membrane into which the cytoplasm flows • Cyclosis • No cell wall; thus, no uniform shape • Shape changes with movement • Reproduce asexually by mitosis; • Sexually by meiosis • Trophozoite • Motile vegetative stage • Cyst • Latent survival stage

12. Medically important species of this philum • 1-Entamoeba histolytica which causes amoebic dysentery . • The organism produces protective cysts which pass out of the intestines of the infected host and are ingested by the next host (fecal-oral route).

13. Medically important species of this philum • 2-Acanthamoeba . Can infect the eye, blood, spinal cord, and brain and is transmitted by waterborne cysts picked up while swimming in contaminated water, crossing the mucous membranes.

14. 2-Subphylum Mastigophora (Protozoa-flagellates) • Motility via flagella • One or more whip-like filaments move in counter-clockwise fashion creating rapid movement • A flagellum is a complex organelle composed of many smaller tubules • Flagella attach to the cell membrane and derive energy from movement from this membrane • Most numerous of the protozoan types • Several are pathogens of humans • All reproduce asexually; some reproduce sexually

15. Medically important species • a. Giardia lamblia :Can cause a gastrointestinal infection calledgiardiasis.Cysts pass out of the intestines of the infected host and are ingested by the next host (fecal-oral route).

16. Medically important species • b-Trichomonas vaginalisinfects the vagina and the male urinary tract. It does not produce a cysts stage and is usually transmitted by sexual contact.

17. Medically important species • c. Trypanosoma brucei gambienscauses African sleeping sickness and is transmitted by the bite of an infected Tsetse fly.

18. B-The Ciliophora • Protozoa-ciliates • Motility via cilia • Cilia surround the cell; their coordinated movement Uses energy from the cell membran • Two nuclei per cell • Small micronucleus governs sexually reproduction • Large macronucleus governs metabolism and growth • Both nuclei divide during asexual mitosis • Intracellular organelles • Function in digestion and excretion • Only one ciliate pathogen affects humans

19. Pathogenic ciliate • The only pathogenic ciliate is Balantidium coli which causes a diarrhea-type infection. Cysts pass out of the intestines of the infected host and are ingested by the next host (fecal-oral route).

20. C. The Apicomplexans • No established means of movement • Thus, not motile • All are intracellular parasites in a variety of hosts • Several parasitic species affect humans • They possess a complex of organelles called apical complexes • All lack intracellular organelles • All have three things in common • No motility • Sexual and Asexual mode of Reproduction • Intracellular parasites

21. Medically important species • Species of Plasmodium .cause malariaand are transmitted by the bite of an infected female Anophelesmosquito. They reproduces asexually by schizogony in human liver cells and red blood cellsbut also reproduce sexually by gametes in the mosquito.

22. Medically important species • Toxoplasma gondiicauses toxoplasmosis • It can infect most mammals and is contracted by inhaling or ingesting cysts from the feces of infected domestic cats, where the protozoa reproduce both asexually and sexually, or by ingesting raw meat of an infected animal.

23. Medically important species • Cryptosporidium is an intracellular parasite that causes diarrhea, although in people who are immunosuppressed it can also cause respiratory and gallbladder infections. It is transmitted by the fecal-oral route

24. Protozoan Diseases Intestinal Amebiasis.....................Entamoeba histolytica Giardiasis.....................Giardia lamblia Balantidiasis…………...Balantidium coli Crytosporidosis…….….Cryptosporidium parvum Urogenital Trichomoniasis………….Trichomonas vaginalis

25. Protozoan Diseases Blood and Tissue • Malaria ……………………......Plasmodium spp • Meningoencephalitis…..……Naegleria fowleri • Toxoplasmosis…….………...Toxoplasma gondii • Trypanosomiasis • African Sleeping Sickness...Trypanosoma brucei • Chagas Disease......................Trypanosoma cruzi

26. Protozoan Diseases • Leishmaniasis • ●Visceral leishmaniasis( Kala-azar) Leishmania donovanii • ●Cutaneous leishmaniasis Leishmania topica/braziliensis

27. Virulence Factors that Promote Colonization of Protozoans The ability to: 1.Contact host cells;2. Adhere to host cells and resist physical removal;3. Invade host cells;4. Compete for nutrients;5. Resist innate immune defenses such as phagocytosis and complement; and6. Evade adaptive immune defenses.

28. GENERAL PROPERTIES OF HELMINTES

29. HELMINTHS ●The helminths are worm-like parasites. ● Helminths are separated according to their general external shape and the host organ they inhabit. ● The definitive classification is based on the external and internal morphology of egg, larval, and adult stages ●Helminths are multicellular eukaryotes.

30. There are three classes of helminths Nematodes – "roundworms" ● Adult and larval roundworms are bisexual, cylindrical worms. ● They inhabit intestinal and extraintestinal sites. ● The nematodes includeTrichinella, Ascaris, and Enterobius.

31. There are three classes of helminths ● Trematodes – "flukes" ● Adult flukes are leaf-shaped flatworms. Prominent oral and ventral suckers help maintain position. ● The life cycle includes an intermediate host. ● An example is the organism that causesschistosomiasis.

32. There are three classes of helminths Cestodes –pig and cattle "tapeworms" ● Adult tapeworms are elongated, segmented, hermaphroditic flatworms that inhabit the intestinal lumen. ● Larval forms, which are cystic or solid, inhabit extraintestinal tissues

33. NEMATODES ●Some species require an intermediate host to complete development. ● Intestinal nematodes all mature into adults within the human intestinal tract.

34. NEMATODES • The nematodes (nema: thread) are threadlike, nonsegmented parasites., • A few mm to 1m in length, with separated sexes. • They possess a complex tegument and a digestive tract.

35. NEMATODES ● The males are usually smaller than the females and are equipped with copulatory organs that often show features specific to each species.

36. NEMATODES ●Development from the egg includes four larval stages andv four moltings before the adult stage is reached. ●The larval forms of many of these roundworms may be distributed widely throughout the body

37. NEMATODES • Three of the intestinal nematodes are acquired by the ingestion of nematode eggs: ● Trichuris trichiura ("whipworm") ● Ascaris lumbricoides ● Enterobius vermicularis ("pinworm")

38. NEMATODES • Two worms are acquired when their larvae penetrate through the skin, usually of the foot: ● Necator americanus ("hookworm") ● Strongyloides stercoralis

39. NEMATODES • One is acquired by the ingestion of the encysted larvae in muscle (pork meat): Trichinella spiralis

40. NEMATODES Ascaris lumbricoides (Large Roundworm) Causative agent of “ascariosis”

41. Ascaris lumbricoides Occurrence ●The human large roundworm occurs worldwide. ● The main endemic regions, with prevalence rates of approx. 10–90%, include countries in Southeast Asia, Africa, and Latin America. ● Autochthonous infections are rare in central Europe.

42. Ascaris lumbricoides Parasite and Lıfe Cycle ● The adult ascarids living in the small intestine are 15–40cm in length, about as thick as a pencil and of a yellowish pink color.

43. Enterobius vermicularis(Pinworm) Causative agent of enterobiosis (oxyuriosis) Occurrence.The pinworm occurs in all parts of the world and is also a frequent parasite in temperate climate zones and developed countries. The age groups most frequently infected arefive- to nine-year-old childrenand adults

44. Enterobius vermicularis Parasite and Lıfe Cycle Enterobius vermicularis which belongs to the Oxyurida has a conspicuous white color. The males are 2–5mm long, The females 8–13 mm. The long, pointed tail of the female gives the pinworm its name.

45. Enterobius vermicularis

46. Class Trematoda(Flukes) • General characteristics Most of the trematode species that parasitize humans aredorsoventrally flattenedwith an oval to lancet shape,although others have different shapes such as the threadlike schistosomes.

47. Class Trematoda • Most species arehermaphroditic. • Snailsare the first intermediate hosts;some species requirearthropods or fishas second intermediate hosts

48. Class Trematoda Schistosoma (Blood Flukes) Causative agents of schistosomosis or bilharziosis. Schistosomosis (bilharziosis) is one of the most frequent tropical diseases with about 200 million infected persons. The occurrence of schistosomosis depends on the presence of suitable intermediate hosts (freshwater snails).

49. Schistosoma (Blood Flukes) ●Schistosomosis is also known as bilharziosis after the German physician Th. Bilharz, who discovered Schistosoma hematobium in human blood vessels in 1851. ● Schistosomosis occurs endemically in 74 tropical and subtropical countries of Africa, South America, and Asia . ● The number of persons infected with schistosomes is estimated at 200 million(WHO 2008)

50. Schistosoma (Blood Flukes) ● Human infections result from contact with standing or slow-moving bodies of water (freshwater) whenSchistosoma cercariaepenetrate the skin. ● Schistosoma hematobiumcauses urinary schistosomosis. ●S. mansoni, S. japonicum,S. intercalatum, and S. mekongiare the causative agents of intestinal schistosomosis and other forms of the disease.